Christian Heimes wrote:
> Paul Pogonyshev wrote:
> > Hi,
> >
> > Is weak reference callback called immediately after the referenced
> > object is deleted or at arbitrary point in time after that? I.e. is
> > it possible to see a dead reference before the callback is called?
> >
> > More formally, will this ever raise?
> >
> > callback_called = False
> > def note_deletion (ref):
> > callback_called = True
> >
> > x = ...
> > ref = weakref.ref (x, note_deletion)
> >
> > ...
> >
> > if ref () is None and not callback_called:
> > raise RuntimeError ("reference is dead, yet callback hasn't been
> > called yet")
>
> Yes, you'll definitely see a RuntimeError because you forgot to declare
> callback_called as a global variable. :)
Thanks. Any useful answers though?
callback_called = False
def note_deletion (ref):
global callback_called
callback_called = True
x = ...
ref = weakref.ref (x, note_deletion)
...
if ref () is None and not callback_called:
raise RuntimeError ("reference is dead, yet callback hasn't been called
yet")
Paul
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